As network enabled computing systems and networks become ubiquitous and more diverse, so do the data communication requirements of applications that utilize these networks. With this proliferation of computing devices, there is a growing need to provide the necessary Quality of Service (QoS) for these communications services. QoS is generally referred to a resource reservation control mechanisms that allows network applications to maintain the guaranteed level of performance for the data flowing over various networks. Using QoS mechanisms, network access devices, such as modems, routers, switches and network servers, can provide different priority to different applications, users, or data flows, or to guarantee a certain level of performance.
Application network traffic types that may require a specific QoS include streaming multimedia, IP telephony, gaming, and others. Each type of network traffic may requires a different type of data delivery service. For example, streaming multimedia typically requires a high guaranteed throughput with reliable data delivery and a low level of variability of delay. On the other hand, IP telephony typically require strict limits on delay and jitter, but is much more tolerant of data loss. Therefore, it is desirable for the networks to provide different QoS to each application in order to meet the user's expectations and provide a good user experience for that specific application.
One know approach for a QoS-aware application to establish and maintain the necessary QoS for its network traffic is though QoS Application Programming Interfaces (API) of the computing device on which the application runs. Typically, computing devices provide QoS APIs as part of an Operating Systems (OS) or platform specific library or service. Therefore, such QoS APIs are inherently OS or platform specific. Given this, it is difficult to design network applications with a QoS support across various OS, platforms and networks. Attempts to do so typically result in an very complicated APIs or APIs with level of QoS coarseness and transparency that is too abstracted to provide any meaningful specification of QoS levels to the application.
This abstraction invariably results with the QoS API forgoing detailed control monitoring of the MAC layer functions. In the ISO OSI architecture, Medium Access Control (MAC) functions govern the device's ability to access the network and have a significant impact on the overall QoS of the data communications service. In addition, MAC functions measure dynamic conditions of the network, such as level of interference and signal strength and, thus, crucial in monitoring levels of QoS of the network traffic. Therefore, to ensure effective and successful support of QoS for network applications, it is desirable for the MAC functions to be part of the QoS service solution.